Tehran University Medical Journal

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Background: Pulmonary Nocardiosis is an infrequent infection whose incidence seems to be on the rise due to a higher degree of clinical suspicion and to an increasing number of immunosuppressive factors. The present investigation was carried out to detect Nocardiosis in immunocompromised patients confined in the pulmonary ward of Tehran’s Shariati Training Hospital through the use of indirect immunofluorescence assay (IFA) and bacterial culture methods. The comparison of the two methods and the correlation between the antibody titer and the statistical and epidemiological data were also investigated.

Materials and Methods: 101 patients with advanced symptomatic pulmonary infection were studied in the course of a twenty-month period. Individual patients’ sputum, BAL (bronchoalveolar lavage) and blood sera were tested. From each sample three thin smears were prepared for microscopic observations. The samples were cultured in Sabouraud’s dextrose, blood and paraffin agar. The detection of antibody against Nocardia asteroides was carried out in all study groups, using the IFA method. The medical history of patients was also obtained through questionnaires for further analysis.

Results: Nocardia asteroides was isolated from only one patient suffering from Wagner vasculitis with an antibody titer of in serum. The 41 patients suspected for Nocardiosis with an antibody titer ranging from to , detected by IFA method, included 26 (63.4%) men and 15 (14.8%) women. The age of the patients varied from 7-80 years. Those with reasonable antibody titers included 15 (36.5%) housewives and 9 (21.9%) workers. Furthermore, in-vitro investigation for the differentiation of the isolates was performed and confirmed the notion that the organism which grew on the primary media was, indeed, the Nocardia asteroids complex.

Conclusion: Our results revealed that the broncho-pulmonary infections, which occur in high-risk patients -T-cell deficiencies, long term corticosteroid therapy, immunocompromised hosts, HIV infection, organ transplantation- was an important index for the primary diagnosis of Nocardiosis. As the important finding of the present research, the antibody titer of could be proposed as the criterion for the diagnosis of the infection. The probability of Nocardiosis was proposed when antibody titer was less or more than .

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Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background: Nocardiosis is a rare and potentially life-threatening infection caused by several species of the Nocardia genus. The objective of this study was to develop and evaluate a rapid and new method to clinically identify relevant Nocardia species. Rapid and accurate diagnosis of Nocardia species is essential for the treatment of severe infections and prevention of cerebral abscess.
Methods:  One hundred and eighty patients, 103 (57.22%) male and 77 (42.78%) female, with severe symptomatic pulmonary infection were studied in the course of a 12-month period in Dr. Shariati Teaching Hospital affiliated to Tehran University of Medical Sciences in 2010. The specimens were cultured and identified using microbiological and biochemical tests. Polymerase chain reaction (PCR) was used to directly identify the organism in the broncoalveolar lavage samples collected from the patients. NG1 and NG2 primers were used to amplify a Nocardia genus-specific 598-bp fragment of 16S rRNA.
Results:  Nineteen samples (10.56%) were positive with PCR and 5 samples (2.78%) with conventional methods. All samples with positive cultures were also positive by PCR.
Conclusion: The results of this study showed that PCR has a high sensitivity and accuracy for the detection of Nocardia compared with culture and biochemical tests. Considering the rapidity, precision, high sensitivity and specificity of molecular techniques, use of these techniques is suggested in conjunction with conventional methods for the detection of Nocardia phenotypes in clinical laboratories and research centers.

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Background: Nocardia species are Gram-positive, partially acid fast, non-motile, catalase positive, aerobic and saprophytic actinomycetes found all around the world. They invade the human body from the environment via trauma and respiratory tract and cause cutaneous, pulmonary and systemic diseases. They are able to grow in various media.The organisms opportunistically infect both immunocompromised and immunocompetent individuals. Behcet's disease is an autoimmune disease and immunocompromised patient which may suitable host for Nocardia bacterium. The present study is the first case report of isolation of Nocardia from the thigh abscess in a patient with behcet’s disease from Iran.
Case Presentation: A 39-year-old man with Behcet’s disease in August 2011 was admitted to Shariati hospital Tehran, with swelling and pain in the left flank and left thigh. Microscopic identification from direct microbiological slide of thigh abscess discharge demonstrated number of lymphocytes, neutrophils and macrophages foamy and white blood cells together with filamentous bacteria. Further microbiological characterization using phenotypic and antibiogram tests with disk diffusion method, demonstrated that the isolated bacterium is Nocardia asteroides complex. The bacteria were sensitive to ampicillin, vancomycin, ceftriaxone, amikacin and cotrimoxazole but it was resistant to clindamycin, erythromycin, penicillin G, cephalothin and gentamicin. The patient was treated with cotrimoxazole.
Conclusion: Because of the high incidence and high mortality of Nocardia infection in immunocompromised cases, rapid detection and timely treatment for these patients is necessary.